Respiratory

Name the structures of the conducting zone.

Trachea, Bronchi, Bronchioles

What are the main functions of the conducting zone?

Air flow - filter, warm, and humidify the air

Name the structure of the respiratory zone.

Respiratory bronchioles, alveolar ducts, alveolar sacs

What is the primary function of the respiratory zone?

Facilitate gas exchange

The conducting zone of the respiratory system includes all of the following except:

Which type of alveolar cell is responsible for producing pulmonary surfactants?

Type 2 alveolar cells

Which lung volume represents the air inhaled during normal, quiet breathing?

Tidal volume

Which lung volume cannot be measured directly by simple spirometry?

Residual volume

Vital capacity is best defined as:

Maximum air exhaled after a maximal inspiration

Total lung capacity is equal to:

VC + RV

A decrease in which lung parameter is most characteristic of restrictive lung disease?

Vital capacity

Functional Residual Capacity consists of:

ERV + RV

A patient with pulmonary fibrosis shows reduced lung compliance. Which of the following parameters is most likely decreased?

Total lung capacity

In emphysema, which lung volume is typically increased due to air trapping?

Residual volume

A bronchodilator improves airflow in an asthmatic patient. Which lung parameter is most directly affected?

Airway resistance

Mr. X has the following parameters: TV = 500 mL, IRV = 3000 mL, ERV = 1100 mL, what is his vital capacity?

VC = TV + IRV + ERV = 500 + 3000 + 1100 = 4600 mL

If VC = 4600 mL and RV = 1200 mL, calculate total lung capacity.

TLC = VC + RV = 4600 + 1200 = 5800 mL

Which structures of the airway are not involved in gas exchange in healthy patients?

Cartilaginous structures (conducting airways)

Anatomic dead space measures the volume of air in the airways.

Conducting

Functional dead space measures the volume of air not engaged in gas exchange.

Alveolar

Physiological dead space can be considered “total dead space” and measures + dead space.

Anatomic + Functional

Inspiratory Reserve Volume

IRV, 3000 mL

Tidal Volume

TV, 500 mL

Expiratory Reserve Volume

ERV, 1200 mL

Residual Volume

RV, 1200 mL

Inspiratory capacity

IC = IRV + TV, 3500 mL

Functional Residual Capacity

FRC = ERV + RV, 2400 mL

Vital Capacity

VC = TV + IRV + ERV, 4700 mL

Total Lung Capacity

TLC = VC + RV, 6000 mL

Limitation of functional residual capacity (FRC) test

Underestimates lung volumes in obstruction

Distensibility of the lungs and chest wall is inversely correlated with the

elastance

Intrapulmonary pressure (alveolar) is

negative or positive

Intrapleural pressure (within the pleural cavity) is

always negative

Transmural pressure is

always positive

Transmural pressure =

Intrapulmonary pressure - Intrapleural pressure